Chlamydophila psittaci (C. psittaci) is an intracellular pathogen and a member of the Chlamydiaceae family that is most frequently associated with Psittaciformes. C. psittaci can infect 465 avian species in 30 avian orders, but the at least 153 species in the order Psittaciformes can also infect a wide range of mammalian hosts. C. psittaci has the ability to remain infectious in the environment for months, which can cause economically devastating outbreaks in poultry farms and respiratory disease (psittacosis) in both mammals and birds. Transmission of this respiratory pathogen can occur through direct contact with infected birds, bird feces, nasal discharges, and aerosols. Zoonotic infections in humans usually result from close contact with infected captive birds, companion, or free-ranging birds; human-to-human transmission has also been suggested. Regardless of the transmission method, infection may lead to severe pneumonia and a wide spectrum of other medical complications. From 1988 through 2003, a total of 935 human cases of psittacosis were reported to the U.S. Centers for Disease Control and Prevention; most were related to contact with Psittaciformes. Approximately 100 psittacosis cases are reported annually in the United States, and one person may die of this disease each year. Individuals with occupations associated with commercial poultry as well as those with routine contact with companion or aviary birds are considered most at risk for infection. Laboratory-acquired infections also remain a concern.
C. psittaci is currently grouped into seven avian genotypes (A through F and the recently identified genotype, E/B) and two non-avian genotypes (M56 and WC). Recent reclassification of C. psittaci has resulted in the separation of C. abortus and C. caviae into distinct species, although these species are genetically closely related.
There is a need for methods to quickly and reliably detect C. psittaci. This will aid in treatment, as quick diagnosis will improve treatment outcomes.